This R21 developmental/exploratory study examines the relations of social and cultural processes to early-stage drug use in a cohort of ethnic minority youth. There exists a tremendous need to clarify the social and cultural factors that influence drug use in adolescence. Researchers have not been able to develop adequate explanations of racial and ethnic differences in drug prevalence based entirely on our current understanding of psychosocial vulnerability. More detailed knowledge is required regarding the role of social and cultural forces as they influence development of health behaviors. However, theoretical models linking identity processes with drug use suffer from poor conceptualization of major constructs, reliance on cross-sectional designs, and a shortage of psychometrically refined assessments tapping identity processes. In response to these and related concerns, the current study focuses on: (1) developing a psychometrically refined assessment of self-identity processes in two cohorts of ethnic minority youth (N=300 middle school and N=300 high school) and (2) prospectively testing the structural relations between ethnic identity, psychosocial risk, and drug use using a short-longitudinal panel design (N=2000 combined) with black, Hispanic, and white youth. Refinement of a multi-dimensional assessment of identity uses experimental procedures that tap memory accessibility (implicit cognition tasks such as word pairings), confirmatory measurement modeling to assess factorial and construct validity, and tests of predictive (criterion) validity utilizing panel data with structural equation modeling. The experimental techniques provide a rigorous means to "unpack" the meaning and cultural relevance of ethnic identity items and to insure their developmental appropriateness. The longitudinal modeling provides a means to discern the relative importance of identity mechanisms when cast in a larger etiological framework. Understanding the role of ethnic/cultural factors in the etiology of drug use is an essential step in the construction and delivery of culturally focused interventions targeting ethnic minority youth and will help to forge a necessary bridge between etiology and prevention.